This invention relates to a sliding disk valve. In particular, the sliding disk valve of this invention is designed for an abrasive or erosive environment typically found in pneumatic conveyance of particulate matter or liquid slurries.
In pipeline processing systems where the fluid conveyed causes erosion of the seating surfaces in a valve, certain techniques have been devised to reduce the effects of wear and maintain a seal upon closure.
The displaceable closure member in a slide valve slides against a contact surface within the valve body and typically scrapes the surface to clear material from the seating surfaces. To provide for uniform wear on the seating surface of the closure member, the member includes a contact element in the form of a disk that is mounted to a retainer and free to rotate. This avoids excessive wear of the leading edge of the closure member and distributes wear uniformly around the perimeter contact surface of the disk.
In order to induce the disk to rotate, various mechanisms have been devised including pins within the valve housing that contact the edge of the disk and incrementally rotate the disk on opening the valve, and uniquely configured hubs that incrementally rotate the disk on opening or closing the valve. Rotation of the disk assists in uniform wear on the displaceable closure member, but generally does not greatly improve the wear pattern on the stationary contact surfaces within the valve housing.
The cam-action disk valve of this invention includes a mechanism to generate an oscillating or orbital motion to the disks of the closure member. This orbital motion expands the area of the stationary contact surface that is contacted by the perimeter contact surface of the disks. The greater distribution of wear uniformly over the stationary contact surface prolongs the sealing capability of the valve and therefore extends the service time of the valve before maintenance is required.
The cam-action disk valve of this invention also includes improvements in the design of the seals for the valve stem of the closure member which connects the cam-action disk to an external displacement mechanism. Other features of this improved sliding disk valve are described in greater detail in the Detailed Description of the Preferred Embodiments.